An idea that is currently the focus of attention is to capture a moving image as an image constituted by a synthesis of units referred to as “objects” corresponding to the content of the image. A moving-image encoding scheme referred to as “MPEG-4” is characterized in that it is possible perform encoding on a per-object basis. Efforts to standardize such encoding are currently being made. In accordance with this encoding scheme, both object editing and manipulation are facilitated because the units of processing are objects.
An object can take on any shape and is composed of a combination of shape data representing the shape information of the object, and texture data representing the surface pattern of the object.
A variety of image editing operations are known generally, examples of which are time-sequence substitution, adjustment of color tones and insertion of separate images. In the main, however, editing operations are performed on a frame-by-frame basis. Object extraction using a blue backdrop is known as an example of editing on an object-by-object basis. This involves preparing a blue background at a studio set or the like in advance, effecting segmentation into blue and non-blue portions by a switcher and combining other images with the blue portions.
However, in cases where an object that has been extracted by the blue backdrop method is subjected to manipulation again, it is difficult to execute processing using only image data. Accordingly, when it is desired to manipulate an object again, it is necessary to preserve data indicating the positions of the blue and non-blue portions in advance. In accordance with MPEG-4, shape data is referred to as a shape and the data of the image itself is referred to as texture.
On the other hand, a problem that arises with editing and remanipulation on an object-by-object basis is that two types of data, namely shape data and texture data, must always be processed as a set. Since the processing of texture in particular involves a heavy processing load, another problem is a large delay in presenting a display during manipulation and editing.